fmt: document order of application of %T, %p and the special interfaces Their priority was not documented.
fmt: document order of application of %T, %p and the special interfaces
Their priority was not documented.

Fixes issue 7571.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://codereview.appspot.com/80360043

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang